The invention concerns a wheel having a disk and a rim for a tire and capable of forming with a support ring for the tire tread and the tire, a rolling assembly that can be useful in running when the inflation pressure drops abnormally below the normal pressure of use, called nominal service pressure, which can even become nil.
The principal difficulties encountered in running flat or at low pressure involve the risks of unseating of the beads of the tire and, in particular, of unseating of the bead situated on the outer side of the tire mounted on the outer side of the vehicle on making a turn.
U.S. Pat. No. 6,035,913 describes, by way of example, a wheel intended to solve the above-mentioned problem efficiently. That wheel comprises, seen in meridian section, a rim with first and second rim seats, at least the first rim seat having a generatrix, the axially outer end of which is on a circle of diameter less than the diameter of the circle on which the axially inner end is located, the first rim seat being extended axially outward by a low protrusion or hump and axially inward by a bearing surface intended to receive a tread support ring, and a wheel disk, joined on the side of the first rim seat to the radially inner wall of the rim. That wheel is such that the rim bearing surface, intended to receive the support ring, is equipped with elements in relief separated by recesses or hollows.
Those recesses or hollows in the bearing surface of the support ring are intended to limit the weight of the wheel.
That limitation can, however, prove inadequate, notably in case design imperatives require connecting the outer profile of the disk directly to the outer seat (wheel described as xe2x80x9cfull facexe2x80x9d). That wheel also presents construction difficulties, particularly when it is desired to make a sheet metal wheel.
The invention concerns a wheel which appreciably improves the previous wheel. The wheel of the invention is composed of a rim with first and second rim seats, at least the first rim seat having a generatrix, the axially outer end of which is on a circle of diameter less than the diameter of the circle on which the axially inner end is located, said first rim seat terminating at its axially outward end in a flange and being extended axially inward by a bearing surface intended to receive a tread support ring, and of a wheel disk, joined on the side of the first rim seat to the radially inner wall of the rim. The wheel is characterized in that the rim bearing surface consists of first and second support zones separated by a circumferential groove opening radially outward.
It has been found that the presence of two support zones is sufficient to ensure good stability of certain types of support rings, without the need for the presence of ribs.
The wheel of the present invention has the advantage of significantly reducing the weight of the wheel.
The circumferential groove can advantageously serve as a housing for a pressure monitoring device.
It is also possible to cover the circumferential groove radially on the outside, at least in part, with a cylindrical hoop-shaped support intended to receive a tread support ring.
The wheel has the advantage of presenting two support zones reduced to a minimum, which make possible a remarkable reduction in weight. In that wheel the bearing function of the support ring is secured by a generally ring-shaped support, containing holes or not, and which can be in one piece with the wheel removably or not or even with the support ring. That makes it possible to design full-face wheels of acceptable weight.
The wheel according to the invention can have a rim made from steel or aluminum alloy sheet metal. The disk can also be made from such sheet metal. The connection between the disk and the rim is then advantageously made by insertion under the circumferential groove.
The invention will be better understood by means of the attached drawings, illustrating nonlimitative working examples of a wheel designed for mounting of a 185/610 R 400 tire.